Health

Doxazosin for treatment of hypertension

Article Abstract:

The drug doxazosin prevents the activation of alpha adrenergic receptors, which are cell membrane proteins that cause constriction of blood vessels when activated. Doxazosin is similar to prazosin and terazosin, and was recently approved for treating high blood pressure (hypertension). Doxazosin acts for a long period of time, and elimination of 50 percent of the administered dose from the body requires 20 hours. The drug is absorbed well from the gastrointestinal tract, but is partially metabolized in the liver, decreasing the amount available for biological activity to 65 percent. Most of the drug present in the blood bonds to blood proteins. The drug's maximum effect to lower blood pressure occurs within two to four hours after oral administration. Doxazosin was shown to have a similar antihypertensive effect as prasozin, terazosin, hydrochlorothiazide, atenolol, metoprolol, nadolol, and enalapril. The new drug is more effective when the patient is in the standing position than in the supine position. Tolerance, or decreased response, to doxazosin did not develop after three years of therapy, and effectiveness was not decreased in older patients or blacks. Doxazosin decreases total and low-density lipoprotein cholesterol and the ratio of total cholesterol to high density lipoproteins. Blood glucose was also decreased by doxazosin. Adverse side effects include a profound drop in blood pressure upon standing and fainting, which can occur within one to three hours after the first dose. The recommended dosage of doxazosin is described. Although doxazosin has a longer duration of action than terazosin and causes less fainting, it is not considered a first choice for treating hypertension. (Consumer Summary produced by Reliance Medical Information, Inc.)

Carteolol and penbutolol for hypertension

Article Abstract:

Carteolol and penbutolol are oral, partial agonist, beta-adrenergic blocking drugs recently approved by the United States Food and Drug Administration for treating hypertension, or abnormally high blood pressure. The doses of these agents required to effectively lower high blood pressure may also cause bronchospasm, or constriction of the bronchi which connect the upper respiratory tract with the lungs. Because carteolol and penbutolol are partial agonists, they may activate the sympathetic nervous system, which controls involuntary body functions during stress; partial agonists cause less slowing of the heart rate and fewer lipid or fat abnormalities than other types of beta blockers. Both antihypertensive drugs are absorbed by the gastrointestinal tract and reach their highest levels in the blood within one to three hours. Carteolol is excreted by the kidney, and penbutolol is metabolized in the liver. Both drugs are eliminated by 50 percent within five to six hours. Carteolol and penbutolol do not cause serious side effects, but may produce effects common to all beta blockers including heart failure, hypotension, or an abnormal drop in blood pressure, and abnormalities in the electrical activity of the heart. Sudden discontinuation of the drugs may result in worsening of angina pectoris, or chest pain resulting from myocardial ischemia, the insufficient supply of blood to the heart. The use of carteolol and penbutolol by nursing mothers is not recommended. The appropriate doses of these antihypertensive agents are discussed. (Consumer Summary produced by Reliance Medical Information, Inc.)

Drugs for hypertension

Article Abstract:

All anti-hypertensive drugs available in the US as of March, 2001 are listed, along with dosage, cost, and side effects. The list includes ACE inhibitors, beta blockers, angiotensin II receptor blockers, diuretics, calcium-channel blockers, vasodilators, alpha blockers, central alpha agonists, and various combinations of these classes.